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ARS Home » Northeast Area » Beltsville, Maryland (BARC) » Beltsville Agricultural Research Center » Environmental Microbial & Food Safety Laboratory » Research » Publications at this Location » Publication #305113

Title: Screening of adulterants in milk powder using a high-throughput Raman chemical imaging method

item QIN, JIANWEI - University Of Maryland
item Chao, Kuanglin - Kevin Chao
item Kim, Moon

Submitted to: ASABE Annual International Meeting
Publication Type: Proceedings
Publication Acceptance Date: 7/1/2014
Publication Date: 7/13/2014
Citation: Qin, J., Chao, K., Kim, M.S. 2014. Screening of adulterants in milk powder using a high-throughput Raman chemical imaging method. ASABE Paper No. 141897627. American Society of Agricultural Biologists and Engineers, St. Joseph, MI.

Interpretive Summary:

Technical Abstract: Milk is one of the most common targets for economically motivated adulteration. Adulterants in milk can cause illness and death when consumed, thus rapid and accurate detection method is needed for authenticating milk products. Our previous studies based on a point-scan Raman imaging system have demonstrated that Raman chemical imaging can be used to detect various adulterants in milk powder. One limitation of our previous approach is the long sampling time (typically in hours) due to the point-scan image acquisition in two spatial dimensions, which prevents the point-scan system from performing fast inspection for the milk powder. In this study, a line-scan Raman chemical imaging system was developed to enable high-throughput screening of the milk powder. The system uses a 785 nm line laser to project a 24 cm long excitation line on the sample surface. Raman scattering signals along the laser line are collected by a detection module consisting of a lens, a dispersive Raman imaging spectrograph, and a CCD camera. A hypercube is accumulated line by line as a motorized table moves the samples transversely through the laser line. Compared to the point-scan system, the line-scan system is capable of imaging a larger sample area with a shorter sampling time (e.g., reducing scan time from hours to minutes). The line-scan system was used to collect Raman images from milk powder mixed with two types of adulterants (i.e., melamine and dicyandiamide). Image processing algorithms were developed to create chemical images of the adulterant particles in the milk powder.